Cardiopulmonary bypass device and method

ABSTRACT

A method and system for performing a cardiopulmonary bypass procedure are provided. The method includes accessing a source of blood in a patient body from which source the blood is to be passed through a cardiopulmonary bypass machine, drawing blood from the source through the cardiopulmonary bypass machine and introducing the blood into an aortic artery of the patient body through a plurality of separate passages, after the blood has been passed through the cardiopulmonary bypass machine. The system comprises a cardiopulmonary bypass machine, a tubular member coupled to an outlet port of the cardiopulmonary bypass machine and a plurality of separate needle members connected in fluid flow communication with the tubular member, the needle members being arranged to be connected in fluid flow communication with an aortic artery, during a cardiopulmonary bypass procedure.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication No. 60/109,325, filed Nov. 20, 1998, the full disclosure ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of heart surgery. In particular,this invention provides a cardiopulmonary bypass device and method forreturning oxygenated blood to the aorta artery, after the blood has beendrawn from, for example, the vena cava veins or right atrium of a heart.The cardiopulmonary bypass device and method of the invention canadvantageously be used in cardiopulmonary bypass performed duringminimal invasive cardiovascular surgery with cardioplegia.

2. Description of the Prior Art

Cardiac surgery relates to surgical procedures performed on a patient'sheart. To perform such cardiac procedures, the heart is sometimesstopped so that the desired surgical procedure can be performed on agenerally stationary heart. Such stopping of the heart is often referredto as cardioplegia. To maintain blood circulation through a patient bodywhile the heart is stopped, a cardiopulmonary bypass is often employed.Traditionally, in the case of open heart surgery, the chest is openedusing a median sternotomy to gain access to the heart. In open heartsurgery, access to, for example, the aorta, for cross clamping purposesfor pulmonary bypass and/or the like, is readily provided. Beforestopping the heart, an arterial cannula is typically connected in fluidflow communication with the aorta artery and a venous cannula istypically connected in fluid flow communication with the superior andinferior vena cava veins. The arterial cannula and the venous cannulastypically define apertures of about 0.5 inch in diameter. The cannulaeare typically connected to a cardiopulmonary bypass (CPB) system so asto perform cardiopulmonary bypass. In cardiovascular bypass, blood isdrawn from the vena cava veins of a patient undergoing coronary surgery.Thereafter, the blood is passed through a venous reservoir and throughan oxygenator or artificial lung where it is oxygenated. A major portionof this oxygenated blood is typically filtered and returned to thepatient's aorta artery for circulation throughout the body. Thus, theCPB system typically takes over the functions of the heart and the lungsof the patient by oxygenating and pumping the blood through the patientbody while the patient's heart is bypassed and stopped.

Once the CPB system is operatively connected to the patient and broughtinto operation, the ascending aorta artery is typically cross clamped toisolate the coronary arteries from the rest of the arterial system.Thereafter, cardiac arrest is induced by typically injecting 500 to 1000cc of cardioplegic solution into an aortic root using a needle orcannula which pierces the wall of the ascending aorta artery upstream ofthe cross clamp. Cardioplegic solution typically comprises aqueoussolutions of potassium chloride and often contains additional substancessuch as dextrose, glutamate, aspartate, and various other electrolytessuch as Ca⁺² and Mg⁺². The punctures of the 0.5 inch diameter venouscannulae and the arterial cannula on the two vena cava veins and on theaorta artery, respectively, often require repair before the heart can berestarted. This is typically accomplished by means of suturing. Aftersuch suturing, and after the heart is then restarted, the sutures needto be closely monitored so as to ensure that the punctures have beenadequately repaired thereby to inhibit rupturing and internal bleedingafter completion of the surgery.

Typically, the foregoing procedure does not present a large problem whenopen chest heart surgery is to be performed since the surgeon isprovided with ready access to the vena cava veins and the aorta artery.However, it can happen that the surgical procedure is to be performed ina manner other than open surgery. Accordingly, in such a case, and wherepulmonary bypass is required, ready access to the vena cava veins andthe aorta artery may not be readily available. This is typically thecase where, for example, the surgical procedure is to be performed in aminimally invasive surgical manner.

Minimally invasive surgery is a relatively recent and very importantdevelopment in the field of surgery. Generally, minimally invasivesurgical techniques use endoscopic or transluminal surgical approachesin performing surgery so as to inhibit trauma and morbidity associatedwith relatively more invasive surgical techniques such as the open heartsurgical technique described above. Minimally invasive surgicaltechniques have been, and are in the process of being, developed toperform surgical procedures by means of endoscopic or transluminaltechniques. It is desirable that myocardial protection andcardiopulmonary support are catered for in a minimally invasive mannerto obviate the need to open the patient's chest, so as to permit thecardiac procedure to be conducted fully in a minimally invasive manner.Current methods of cardioplegia and performing cardiopulmonary bypass donot adequately meet this desire as evidenced in the following prior artU.S. patents, the full disclosures of which are fully incorporatedherein by reference: U.S. Pat. No. 4,712,551 to Rayhanabad; U.S. Pat.No. 4,979,937 to Khoransani; U.S. Pat. No. 5,190,538 to Fonger et al.;U.S. Pat. No. 5,466,216 to Brown et al.; and U.S. Pat. No. 5,695,457 toSt. Goar et al.

U.S. Pat. No. 4,712,551 to Rayhanabad discloses a vascular shunt havinga plurality of branches. The various embodiments of the vascular shuntare depicted in FIGS. 1 and 8 of this patent.

U.S. Pat. No. 4,979,937 to Khoransani discloses a plurality of smallcannulas connected to Y-connectors and to larger cannulas for providingblood flow during aortic procedures. More specifically, and as can bestbe seen with reference to FIGS. 1 and 2 of this patent, there is seen anintercostal and lumbar perfusion apparatus having a main member and aplurality of side members communicating with the main member via aY-connector. The apparatus disclosed in this patent provides blood flowto distal organs and intercostals during aortic surgery.

U.S. Pat. No. 5,190,538 to Fonger et al. discloses a cannula within theleft atrium of the heart for draining blood and returning it via anarterial cannula after passing through an extra-corporeal pump. Theatrium of the heart is pierced by a needle assembly to enable insertionof a catheter and the cannula.

U.S. Pat. No. 5,466,216 to Brown et al. discloses a pair of cannulae,respectively, inserted into the aortic root and the coronary sinus of aheart (see FIG. 1). A system or assembly interconnects the two cannulaefor delivery of blood and cardioplegic solution to the aortic root forantegrade infusion or to the coronary sinus for retrograde infusion.

U.S. Pat. No. 5,695,547 to St. Goar et al. discloses a completecardioplegia and cardiopulmonary bypass system. The devices disclosed inthis patent induce cardioplegic arrest for myocardial protection duringcardiac surgery by direct perfusion of the coronary arteries using atransluminal approach from a peripheral arterial entry point.

The prior art above does not teach a method or an apparatus wherebycardiopulmonary bypass can be performed without having to repair cannulapunctures in the aorta artery and the vena cava veins after terminationof a cardiopulmonary bypass procedure.

It is an object of the present invention to provide a method ofperforming cardiovascular bypass for cardiac surgery with cardioplegia.

It is another object of the present invention to provide a method ofperforming cardiopulmonary bypass for minimal invasive cardiovascularsurgery with cardioplegia.

It is another object of the present invention to provide acardiopulmonary bypass system.

It is another object of this invention to provide an apparatus andmethod whereby cardiopulmonary bypass can be performed without having torepair punctures in the aorta after the cardiopulmonary bypass has beencompleted. It is a further object of the invention to provide acardiopulmonary bypass apparatus and method which also inhibits havingto repair punctures in the vena cava veins upon completion of thecardiopulmonary bypass procedure.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a method of performing acardiopulmonary bypass procedure is provided. The method includesaccessing a source of blood in a patient body from which source theblood is to be passed through a cardiopulmonary bypass machine, drawingblood from the source through the cardiopulmonary bypass machine andintroducing the blood into an aortic artery of the patient body througha plurality of separate passages, after the blood has been passedthrough the cardiopulmonary bypass machine.

According to another aspect of the invention, there is provided acardiopulmonary bypass system comprising a cardiopulmonary bypassmachine, a tubular member coupled to an outlet port of thecardiopulmonary bypass machine and a plurality of separate needlemembers connected in fluid flow communication with the tubular member,the needle members being arranged to be connected in fluid flowcommunication with an aortic artery, during a cardiopulmonary bypassprocedure.

According to yet a further aspect of the invention, there is provided amethod of performing cardiovascular bypass for cardiac surgery withcardioplegia, the method comprising the steps of:

a) inserting a plurality of needle members into a right atrium of apatient's heart;

b) flowing blood from the right atrium of the patient's heart, throughthe plurality of needle members, and to a cardiopulmonary bypass machinewhere the blood is oxygenated to produce oxygenated blood; and

c) flowing the oxygenated blood of step (b) into an aorta arteryextending from the patient's heart such that cardiovascular bypass isperformed for cardiac surgery with cardioplegia.

The immediate foregoing method may additionally comprise inserting,prior to the flowing step (c), a plurality of a aorta needle membersinto the aorta artery extending from the patient's heart. The flowingstep (c) may comprise flowing oxygenated blood through the aorta needlemembers and into the aorta artery. Preferably, the aorta artery isoccluded (e.g., such as by pinching the aorta artery) at a locationbetween the patient's heart and the aorta needle members. In a preferredembodiment of the invention, the inserting step (a) includes insertingthe needle members into a right auricle of the patient's heart. Theneedle members may each be dimensioned with an inside diameter such thateach needle member has blood flowing therethrough at a respectivevolumetric flow rate. Similarly, the aorta needle members may each bedimensioned with an inside diameter such that each aorta needle memberhas blood flowing therethrough also at a respective volumetric flowrate. The needle members may communicate with a tubular member whichpreferably may be dimensioned with an internal diameter such that theblood flowing through the tubular member has a volumetric flow rate thatis approximately equal to the sum of the respective volumetric flowrates of the blood flowing through the plurality of needle members.Similarly, the aorta needle members may communicate with a tubularmember that may be dimensioned with an internal diameter such that theoxygenated blood flowing through the tubular member has a volumetricflow rate that is approximately equal to the respective volumetric flowrates of the oxygenated blood flowing through the plurality of aortaneedle members.

According to yet another aspect of the invention, there is provided amethod of performing cardiopulmonary bypass for minimal invasivecardiovascular surgery with cardioplegia, the method comprising thesteps of:

(a) providing a plurality of first needle members communicating with afirst tubular member which is coupled to a cardiopulmonary bypassassembly;

(b) providing a plurality of second needle members communicating with asecond tubular member which is coupled to the cardiopulmonary bypassassembly;

(c) providing a plurality of third needle members communicating with athird tubular member which is coupled to the cardiopulmonary bypassassembly;

(d) inserting a plurality of first needle members into a superior venacava vein extending to a heart of a patient;

(e) inserting a plurality of second needle members into an inferior venacava vein extending to the heart of the patient;

(f) inserting the plurality of third needle members into an aorta arteryextending from the heart of the patient;

(g) occluding the superior vena cava vein at a location between thefirst needle members of step (d) and the heart of the patient, causingblood to flow from the superior vena cava vein, through the first needlemembers, and through the first tubular member to the cardiopulmonarybypass assembly where the blood is oxygenated;

(h) occluding the inferior vena cava vein at a location between thesecond needle members of step (e) and the heart of the patient, causingblood to flow from the inferior vena cava vein, through the secondneedle members, and through the second tubular member to thecardiopulmonary bypass assembly where the blood is oxygenated;

(i) occluding the aorta artery at a location between the third needlemembers of step (f) and the heart of the patient; and

(j) flowing oxygenated blood from the cardiopulmonary bypass assembly,through the third tubular member, and through the third needle membersand into the aorta artery such that cardiopulmonary bypass is performedfor minimal invasive cardiovascular surgery with cardioplegia.

According to yet a further aspect of the invention, there is provided acardiopulmonary bypass system comprising a cardiopulmonary bypassassembly, a first tubular member coupled to the cardiopulmonary bypassassembly and a plurality of first needle members coupled to the firsttubular member, a second tubular member also coupled to thecardiopulmonary bypass assembly and a plurality of second needle memberscoupled to the second tubular member.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying diagrammatic drawings, in which:

FIG. 1 shows an elevational view of a human heart;

FIG. 2A shows a schematic diagram of a cardiopulmonary bypass system, inaccordance with the invention, which includes needle devices also inaccordance with the invention;

FIG. 2B shows, at an enlarged scale, a sectional view taken along arrows2B—2B in FIG. 2A;

FIG. 3 shows, at an enlarged scale, a sectional view of a superior venacava vein in fluid flow communication with a human heart of a patient,and further shows a plurality of needle members extending into thesuperior vena cava vein, in accordance with one aspect of the invention,such that blood can be drawn from the superior vena cava vein throughthe needle members during cardiopulmonary bypass;

FIG. 4 shows, at an enlarged scale, a sectional view of an inferior venacava vein in fluid flow communication with a human heart of a patient,and further shows a plurality of needle members extending into theinferior vena cava vein, in accordance with another aspect of theinvention, such that blood can be drawn from the inferior vena cava veinduring cardiopulmonary bypass in accordance with the invention;

FIG. 5 shows, at an enlarged scale, a sectional view of an aorta arteryin fluid flow communication with a human heart of a patient, and shows aplurality of aorta needle members extending into the aorta artery, inaccordance with the invention, such that blood can be introduced intothe aorta through the needle members, during cardiopulmonary bypass inaccordance with the invention;

FIG. 6 corresponds to FIG. 3 and shows the superior vena cava vein beingoccluded by pinching it at a location between the needle members and thehuman heart;

FIG. 7 corresponds to FIG. 4 and shows the inferior vena cava veinoccluded by pinching at the location between the needle members and thehuman heart;

FIG. 8 corresponds to FIG. 5 and shows the aorta being occluded bypinching at the location between the aorta needle members and the humanheart; and

FIG. 9 corresponds to FIG. 1 and shows a plurality of needle memberspiercing the right auricle of the right atrium of the human heart.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be described with reference to FIGS. 1-9. InFIGS. 1-9, like reference numerals are used to designate similar partsunless otherwise stated. Although the present invention will now bedescribed in the context of both delivering oxygen-depleted blood to acardiopulmonary bypass machine and returning oxygenated blood from thebypass machine to the patient's circulatory system, e.g., a patient'saorta, without having to repair punctures in the various vessels or bodyorgans to which the invention is applied, it should be understood thatthe invention will provide distinct advantages over the existing systemsand methods for returning oxygenated blood to the patient even ifanother method of cannulating the patient's venous system is used as asource of blood for the bypass machine. In addition, it should beunderstood that the practice of this invention is not limited solely tominimally invasive procedures, but instead has application to anyoperation in which the surgeon desires to acquire a source of bloodfrom, and/or deliver blood or other fluids (such as, e.g., saline orpharmaceutical-laced fluids) to a patient's body, most preferably to thepatient's circulatory system.

Referring to FIG. 1, a human heart is generally indicated by referencenumeral 8. Referring to FIG. 2A, a cardiovascular bypass system inaccordance with the invention, is generally indicated by referencenumeral 10. The system 10 of the invention utilizes needle assemblies toaccess the superior and inferior vena cava veins and aorta arteryrespectively so as to perform cardiopulmonary bypass.

Referring again to FIG. 1, the superior vena cava vein is indicated byreference numeral 14 and the inferior vena cava vein is indicated byreference numeral 16. The veins 14, 16 are connected in fluid flowcommunication with the heart 8. The superior vena cava 14 and theinferior vena cava 16 feed blood to the heart after the blood has beencirculated throughout a patient body (not shown). The right atrium ofthe heart 8 is shown at 9, and the right auricle is indicated at 9 a.The aorta artery is indicated at 11 and is connected in fluid flowcommunication with the heart to feed blood from the heart into thecirculation system of the patient body. The right ventricle of the heartis indicated at 13, the left atrium at 15, and the left auricle at 15 a.A pulmonary trunk is indicated at 17.

The cardiovascular bypass system 10, in accordance with the invention,will now be described in greater detail with reference to FIG. 2A. Thesystem 10 includes needle assemblies generally indicated at 60, 64, and68, respectively. The needle assemblies 60, 64 are arranged to accessand draw blood from the superior vena cava 14 and the inferior vena cava16, respectively. The needle assembly 60 comprises a plurality of accessneedles 18 a, 18 b, 18 c, 18 d, generally indicated at 18, each of whichis connected in fluid flow communication with a tube assembly, generallyindicated at 70. The tube assembly 70 comprises tubes 70 a, 70 b, 70 c,70 d, each of which is connected in fluid flow communication with asingle tube 72. Each of the needles 18 is connected to a free end of oneof the tubes of the tube assembly 70.

Needle assembly 64 includes a plurality of access needles 19 a, 19 b, 19c, 19 d, which are generally indicated at 19. The needles at 19 areconnected in fluid flow communication with a tube assembly, generallyindicated at 74. The tube assembly 74 is connected in fluid flowcommunication with a tube 76. The tube assembly 74 includes a pluralityof tube members 74 a, 74 b, 74 c, 74 d, each of which is connected influid flow communication with the tube 76. The needles 19 are connectedin fluid flow communication with free ends of the tubes at 74.

The tubes 72, 76 are connected in fluid flow communication with a tube75. Advantageously, back pressure, uniflow, or check valves 72 a, 76 a,can be provided to inhibit backflow of blood therethrough.

The needle assembly 68 is arranged to feed oxygenated blood to the aortaartery 11. Needle assembly 68 comprises a plurality of needles 21 a, 21b, 21 c, 21 d, generally indicated by reference numeral 21, each ofwhich is connected in fluid flow communication with a tube assembly 78.The tube assembly 78 includes separate tubes 78 a, 78 b, 78 c, 78 d,each of which is connected in fluid flow communication with a commontube 80. Conveniently, a backpressure valve 82 can be provided toinhibit back flow of oxygenated blood.

The tubes 75, 80 are connected in fluid flow communication with acardiovascular bypass machine, or assembly, generally indicated at 79.The cardiovascular bypass assembly 79 comprises an oxygenator 100, apump 102, an arterial filter 104, a suction wand 106, a blood oxygensaturation measuring and charting device 108, and a cardiotomy reservoir110. It further comprises an inlet 75 a to which the tube 75 isconnected in fluid flow communication and an outlet 80 a to which thetube 80 is connected in fluid flow communication.

Referring to FIG. 2B of the drawings, each of the needles 18, 19, 21 istypically in the form of a slender surgical needle having a sharp pointor end for piercing tissue. The needles 18, 19, 21 can be made of anyappropriate material, such as steel, stainless steel, or the like. Eachof the needles 18, 19, 21 typically has an outer diameter D_(o) of lessthan about 0.4 inches. Preferably, the needles have an outer diameterD_(o) of less than 0.36 inches. Advantageously, each of the needles 18,19, 21 may have an outer diameter D_(o) falling in the range betweenabout 0.3 inches or less.

The outer diameters D_(o) of the needles 18, 19, 21 are typicallysufficiently small so that when the needles are used to puncture thevena cava veins and the aorta artery respectively, to performcardiopulmonary bypass in accordance with the invention, the puncturesare of a size such that when the needles are withdrawn from the venacava veins and the aorta artery, the punctures do not need to berepaired, e.g., by means of suturing, or the like. In accordance withconventional cardiopulmonary bypass techniques, the arterial cannula andvenous cannulae which are typically used to access the aorta and thevena cava veins, are of a size which, when used during a cardiopulmonarybypass operation, form punctures in the vena cava veins and the aortaartery, respectively, which are of a size which requires repair afterthe cardiopulmonary bypass operation has been completed. It has beenfound that when a needle having an outer diameter of greater than about0.5 inch is used to pierce the vena cava veins or the aorta artery, thenrepair is typically required to seal the puncture. Such repair istypically performed by means of suturing. Each needle typically has asharp end, as can best be seen in FIG. 2B as indicated at E withreference to needle 19 a.

It will be appreciated that each of the needle groups 18, 19, 21 areshown as having four needles for illustrative purposes only. Naturally,the number of needles used can vary and may depend on the internaldiameter D_(i) of each needle, the size of the vena cava veins 14, 16and the aorta artery 11, the blood flow rate of the patient, and thelike.

Each of the tubes of the groups 70, 74, 78 preferably has an internaldiameter corresponding to the internal diameter of the needle attachedto the tube. Accordingly, and as can best be seen with reference to FIG.2B, the tube 74 a has an internal diameter 74 _(id) that is generallyequal to the internal diameter D_(i) of the needle 19 a. Preferably, theindividual needles of the needle groups 18, 19, 21, and the individualtubes of the tube groups 70, 74, 78 are all internally dimensioned withinternal diameters such that there is a generally constant, smoothvolumetric flow rate (e.g., in cc/unit of time) of blood 27 through theindividual needles and their associated tubes. Tubes 72, 76 haveinternal diameters such that the sum of the volumetric flow rates ofblood flowing through the individual tubes 70 a, 70 b, 70 c, 70 d, andindividual tubes 74 a, 74 b, 74 c, 74 d, respectively, generally equalthe volumetric flow rate of blood flowing through the tubes 72 and 76,respectively. Tube 75 is also internally dimensioned with an internaldiameter such that the sum of the volumetric flow rates of blood flowingthrough tubes 72, 76 is generally equal to the volumetric flow rate ofblood flowing through tube 75. Furthermore, tube 80 typically has aninternal diameter such that the volumetric flow rate of blood flowingthrough the tube 80 is preferably about equal to the sum of thevolumetric flow rates of blood flowing through the individual tubes 78a, 78 b, 78 c, 78 d.

It will be appreciated that the number of needles 18, 19, 21 and theirinternal diameters D_(i) are chosen such that there is a consistent andsmooth drawing of blood from the vena cava veins 14, 16 or from theright atrium 9, and a consistent and smooth supply of oxygenated bloodinto the aorta artery 11, so as to inhibit trauma to the patient.Furthermore, the outside diameters D_(o) of the needles 18, 19, 21 arechosen such that after completion of the cardiopulmonary bypass, repairto the vena cava veins and the aorta artery to seal the punctures afterthe needles have been withdrawn would not be required.

In use, when a cardiopulmonary operation is performed using the system10, the needles 18 a, 18 b, 18 c, 18 d of needle assembly 60 and theneedles 19 a, 19 b, 19 c, 19 d of needle assembly 64 are introduced,preferably minimally invasively, into the superior vena cava 14 (seeFIG. 3) and into the inferior vena cava 16 (see FIG. 4), respectively.With reference to FIG. 9, by way of example, the needles 18 can beinserted into the right auricle 9 a of the right atrium 9 of the heart 8instead of into the superior vena cava 14. It will be appreciated that,instead, the needles 19 can be inserted into the right auricle.Furthermore, alternatively both the needles 18, 19 in combination can beinserted into the right auricle 9 a.

The needles 21 a, 21 b, 21 c, 21 d of the needle assembly 68 areinserted into the aorta artery 11, as can best be seen with reference toFIG. 5.

Once the respective needles have been inserted into the vena cava veinsand the aorta artery, the aorta 11 is typically occluded. Such occlusioncan be achieved in any appropriate manner with any appropriate apparatusor device. In one embodiment of the invention, the vena cava veins 14,16 are respectively occluded by pinching them with pincher devices 120,124 (see FIGS. 6 and 7) at the location on the vena cava vein 14 betweenthe needles 18 a, 18 b, 18 c, 18 d and the heart 8, and at a location onthe vena cava vein 16 between needles 19 a, 19 b, 19 c, 19 d and theheart 8, respectively. The aorta artery 11 is preferably occluded bypinching it with pincher 128 (see FIG. 8) at a location on the aortaartery 11 between needles 21 a, 21 b, 21 c, 21 d and the heart 8.

To perform the cardiopulmonary bypass, blood is then drawn from thesuperior vena cava 14 and the inferior vena cava 16 through the needlegroups 18, 19, respectively. The blood drawn from the vena cava veins14, 16 then flows from the needles 18, 19 through tube assembly 70 andtube assembly 74 and then into the tube 72, 76, and then into the tube75. The blood is then fed to the oxygenator 100 by means of the tube 75,where oxygen is added to the blood and carbon dioxide is removed fromthe blood thereby to simulate the function of the patient's lungs.

Upon exiting the oxygenator 100, a main portion of the oxygenated bloodflows to the pump 102 which pumps the blood to the arterial filter 104.The effectiveness of the oxygenator 100 is measured by an inlineconnection (not shown) to the blood oxygen saturation measuring andcharting device 108. At the arterial filter 104, particulate matter andmicro-air emboli from the oxygenated blood are removed and the filteredoxygenated blood is returned to the body of the patient through the tube80. From the tube 80, blood flows through the tube assembly 78 and thenthrough the needles 21 and into the aorta artery 11. In this manner,blood is circulated through the body while the heart is stopped, thecardiopulmonary system 10 simulating heart and lung function of thepatient. Any blood which escapes the patient's circulatory system duringthe operation, is typically sucked from the chest or pleural cavity bymeans of a suction wand 106. The sucked blood is directed to thecardiotomy reservoir 110. In the cardiotomy reservoir 110, the blood isdefoamed and filtered and fed to the oxygenator 100 to be oxygenated andreturned to the patient, in the manner described above.

Instead of drawing blood from the vena cava veins as described above,and as already mentioned, blood can be withdrawn from the atrium 9 ofthe heart 8. As can best be seen with reference to FIG. 9, the needlesof the needle group 18 can be inserted into the right auricle 9 a of theright atrium 9 of the heart 8. Blood is then caused to flow throughneedles 18, through tube assembly 70 and tube 72, and then through tube75 and into the cardiovascular bypass assembly 79 where the blood isoxygenated, processed and returned to the patient in accordance with themanner described above.

Accordingly, in the manner described above, a method of performingcardiovascular bypass is provided to facilitate cardiac surgery withcardioplegia. While the methods described above have been described byemploying needles 18, tube assembly 70 and tube 72, it is to beappreciated that the same method may be conducted by employing needles19, or a combination of needles 18, 19, and any tube assembly andtube(s) associated therewith. The method(s) of the present invention forperforming cardiovascular bypass may be performed for the purpose ofperforming any type of cardiac surgery with cardioplegia. Thecardiopulmonary bypass system of the invention can advantageously beused to perform cardiopulmonary bypass in accordance with the abovemethod(s) when cardiovascular surgery is to be performed withcardioplegia, in a minimally invasive manner.

Thus, while the present invention has been described with reference toparticular embodiments, a latitude of modification, various changes andsubstitutions are intended in the foregoing disclosure and it will beappreciated that in some instances some features of the invention willbe employed without a corresponding use of other features withoutdeparting from the scope and spirit of the invention as set forth.Therefore, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope and spirit of the present invention.It is intended that the invention not be limited to the particularembodiments disclosed as the best mode contemplates for carrying outthis invention, but that the invention will include all embodiments andequivalents falling within the scope of the appended claims.

What is claimed is:
 1. A method of performing cardiovascular bypass forcardiac surgery with cardioplegia comprising the steps of: a) insertinga plurality of access needle members into a right atrium of a patient'sheart; b) flowing blood along a bypass flow path including the pluralityof access needle members and a cardiopulmonary bypass system where theblood is oxygenated to produce oxygenated blood; and c) flowing theoxygenated blood of step (b) into an aortic artery extending from thepatient's heart such that cardiovascular bypass is performed for cardiacsurgery with cardioplegia.
 2. The method of claim 1, additionallycomprising inserting, prior to said flowing step (c), a plurality ofaortic needle members into the aortic artery extending from thepatient's heart.
 3. The method of claim 2, wherein said flowing step (c)comprises flowing oxygenated blood through the aortic needle members andinto the aortic artery.
 4. The method of claim 3, additionallycomprising occluding the aortic artery at a location between thepatient's heart and the aortic needle members.
 5. The method of claim 4,wherein said occluding comprises pinching the aortic artery.
 6. Themethod of claim 5, wherein said inserting step (a) comprises insertingthe access needle members into a right auricle of the patient's heart.7. The method of claim 4, wherein said aortic needle members are eachdimensioned with an inside diameter such that each aortic needle memberhas blood flowing therethrough at a respective volumetric flow rate. 8.The method of claim 7, wherein said aortic needle members communicatewith a tubular member dimensioned with an internal diameter such thatthe oxygenated blood flowing through the tubular member has a volumetricflow rate that is approximately equal to the sum of the respectivevolumetric flow rates of the oxygenated blood flowing through theplurality of aortic needle members.
 9. The method of claim 2, whereinsaid aortic needle members are each dimensioned with an inside diametersuch that each aortic needle member has blood flowing therethrough at arespective volumetric, flow rate.
 10. The method of claim 9, whereinsaid aortic needle members communicate with a tubular member dimensionedwith an internal diameter such that the oxygenated blood flowing throughthe tubular member has a volumetric flow rate that is approximatelyequal to the sum of the respective volumetric flow rates of theoxygenated blood flowing through the plurality of aortic needle members.11. The method of claim 2, wherein the aortic needle members each havean outer diameter less than about 0.4 inches.
 12. The method of claim 1,wherein said inserting step (a) comprises inserting the access needlemembers into a right auricle of the patient's heart.
 13. The method ofclaim 1, wherein said access needle members are each dimensioned with aninside diameter such that each access needle member has blood flowingtherethrough at a respective volumetric flow rate.
 14. The method ofclaim 13, wherein said access needle members communicate with a tubularmember dimensioned with an internal diameter such that the blood flowingthrough the tubular member has a volumetric flow rate that isapproximately equal to the sum of the respective volumetric flow ratesof the blood flowing through the plurality of access needle members. 15.The method of claim 1, wherein the access needle members each have anouter diameter less than about 0.4 inches.
 16. A method of performing acardiopulmonary bypass procedure, the method comprising: accessing asource of blood in a patient body from which source the blood is to bepassed through a cardiopulmonary bypass machine; drawing blood from thesource through the cardiopulmonary bypass machine; and introducing theblood into an aortic artery of the patient body through a plurality ofseparate passages, after the blood has been passed through thecardiopulmonary bypass machine, wherein each of the plurality ofseparate passages is defined by a needle having an outer diameter lessthan about 0.4 inches, wherein introducing the blood into the aorticartery is carried out by passing the blood through the needles.
 17. Amethod as claimed in claim 16, wherein accessing the source of blood inthe patient body comprises connecting a plurality of access passages influid flow communication with the source.
 18. A method as claimed inclaim 17, wherein each access passage is defined by an access needlehaving a sharp end, connecting the plurality of access passages in fluidflow communication with the source comprising passing the sharp ends ofthe access needles through a wall of the source.
 19. A method as claimedin claim 18, wherein the source comprises a superior vena cava vein, themethod including passing the sharp ends of at least some of the accessneedles through a wall of the superior vena cava vein to establish fluidflow communication between the access needles and the superior vena cavavein.
 20. A method as claimed in claim 18, wherein the source comprisesan inferior vena cava vein, the method including passing the sharp endsof at least some of the access needles through a wall of the inferiorvena cava vein to establish fluid flow communication between the accessneedles and the inferior vena cava vein.
 21. A method as claimed inclaim 18, wherein the source comprises an atrium of the heart, themethod comprising passing the sharp ends of at least some of the accessneedles through a wall of the atrium to establish fluid flowcommunication between the access needles and the atrium.
 22. A method asclaimed in claim 18, wherein the access needles are connected in fluidflow communication with a common passage connected in fluid flowcommunication with the cardiopulmonary machine, drawing blood from thesource comprising drawing blood from the source through the plurality ofaccess needles and then through the common passage into thecardiopulmonary bypass machine.
 23. A method as claimed in claim 18,wherein the access needle members each have an outer diameter less thanabout 0.4 inches.
 24. A method as claimed in claim 16, wherein theneedles are connected in fluid flow communication with a common passage,the common passage being connected in fluid flow communication with thecardiopulmonary bypass machine, introducing the blood into the aorticartery comprising feeding the blood from the cardiopulmonary bypassmachine, through the common passage and then through the needles intothe aortic artery.
 25. A method as claimed in claim 24, wherein theneedles have sharp ends, the method comprising the prior step of passingthe sharp ends of the needles through an arterial wall of the aorticartery to establish fluid flow communication between the needles and theaortic artery.
 26. A method of performing a cardiopulmonary bypassprocedure, the method comprising: accessing a source of blood in apatient body through a plurality of access passages, from which sourcethe blood is to be passed through a cardiopulmonary bypass machine,wherein each access passage is defined by a needle having a sharp end,wherein accessing is carried out by connecting the plurality of accesspassages in fluid flow communication with the source by passing thesharp ends of the needles through a wall of the source; drawing bloodfrom the source through the cardiopulmonary bypass machine; andintroducing the blood into an aortic artery of the patient body througha plurality of separate passages, after the blood has been passedthrough the cardiopulmonary bypass machine.
 27. A method as claimed inclaim 26, wherein the source comprises a superior vena cava vein, themethod including passing the sharp ends of at least some of the needlesthrough a wall of the superior vena cava vein to establish fluid flowcommunication between the needles and the superior vena cava vein.
 28. Amethod as claimed in claim 26, wherein the source comprises an inferiorvena cava vein, the method including passing the sharp ends of at leastsome of the needles through a wall of the inferior vena cava vein toestablish fluid flow communication between the needles and the inferiorvena cava vein.
 29. A method as claimed in claim 26, wherein the sourcecomprises an atrium of the heart, the method comprising passing thesharp ends of at least some of the needles through a wall of the atriumto establish fluid flow communication between the needles and theatrium.
 30. A method as claimed in claim 26, wherein the needles areconnected in fluid flow communication with a common passage connected influid flow communication with the cardiopulmonary machine, drawing bloodfrom the source comprising drawing blood from the source through theplurality of needles and then through the common passage into thecardiopulmonary bypass machine.
 31. A method of performingcardiovascular bypass for cardiac surgery with cardioplegia comprisingthe steps of: a) inserting a plurality of access needle members into aright atrium of a patient's heart; b) flowing blood along a bypass flowpath including the plurality of access needle members and acardiopulmonary bypass system where the blood is oxygenated to produceoxygenated blood; c) inserting a plurality of aortic needle members intoan aortic artery extending from the patient's heart; d) flowing theoxygenated blood of step (b) through the aortic needle members and intothe aortic artery extending from the patient's heart such thatcardiovascular bypass is performed for cardiac surgery withcardioplegia; and e) occluding the aortic artery at a location betweenthe patient's heart and the aortic needle members by pinching the aorticartery.
 32. The method of claim 31, wherein said inserting step (a)comprises inserting the access needle members into a right auricle ofthe patient's right atrium.
 33. A method of performing cardiopulmonarybypass for minimal invasive cardiovascular surgery with cardioplegiacomprising the steps of: a) providing a plurality of first needlemembers communicating with a first tubular member which is coupled to acardiopulmonary bypass assembly; b) providing a plurality of secondneedle members communicating with a second tubular member which iscoupled to the cardiopulmonary bypass assembly; c) providing a pluralityof third needle members communicating with a third tubular member whichis coupled to the cardiopulmonary bypass assembly; d) inserting theplurality of first needle members into a superior vena cava veinextending to a heart of a patient; e) inserting the plurality of secondneedle members into an inferior vena cava vein extending to the heart ofthe patient; f) inserting the plurality of third needle members into anaortic artery extending from the heart of the patient; g) occluding thesuperior vena cava vein at a location between the first needle membersof step (d) and the heart of the patient, causing blood to flow from thesuperior vena cava vein, through the first needle members, and throughthe first tubular member to the cardiopulmonary bypass assembly wherethe blood is oxygenated; h) occluding the inferior vena cava vein at alocation between the second needle members of step (e) and the heart ofthe patient, causing blood to flow from the inferior vena cava vein,through the second needle members, and through the second tubular memberto the cardiopulmonary bypass assembly where the blood is oxygenated; i)occluding the aortic artery at a location between the third needlemembers of step (f) and the heart of the patient; and j) flowingoxygenated blood from the cardiopulmonary bypass assembly, through thethird tubular member, and through the third needle members and into theaortic artery such that cardiopulmonary bypass is performed for minimalinvasive cardiovascular surgery with cardioplegia.
 34. A method ofperforming cardiovascular bypass for cardiac surgery with cardioplegiacomprising the steps of: a) inserting a plurality of needle members intoa right auricle of a patient's heart; b) flowing blood along a bypassflow path including the plurality of needle members and acardiopulmonary bypass system where the blood is oxygenated to produceoxygenated blood; and c) flowing the oxygenated blood of step (b) intoan aortic artery extending from the patient's heart such thatcardiovascular bypass is performed for cardiac surgery withcardioplegia.
 35. A method of performing a cardiopulmonary bypass for aminimally invasive cardiovascular surgery with cardioplegia, the methodcomprising: accessing a source of blood in a patient body through aplurality of access passages, from which source the blood is to bepassed through a cardiopulmonary bypass machine; drawing blood from thesource through the cardiopulmonary bypass machine; and introducing theblood into an aortic artery of the patient body through a plurality ofseparate passages, after the blood has been passed through thecardiopulmonary bypass machine, wherein cardiopulmonary bypass isperformed for minimally invasive cardiovascular surgery withcardioplegia without having to perform any puncture repairs on thesource or aortic artery resulting from the access or separate passagesafter termination of the cardiopulmonary bypass.